The subprime loan mortgage crisis has revived scholarly interest in Minsky s nancial instability hypothesis. The related mathematical models present twotypes of Minskian nancial structures. We construct macrodynamic models thatconsider both structures and discuss nancial instability and cycles. We alsodemonstrate that one of the nancial cycles occurs when a real factor stabilizesthe economy. The burden of interest-bearing debt is an important determinantof the cycle. We posit that the escalating nancial fragility in this cycle is amore appropriate interpretation of the Minskian nancial structure that refers tohedging, speculative and Ponzi behaviors. We further demonstrate that another nancial structure destabilizes the economy. If the instability occurs at the pointof fragility, then the economy may deteriorate into nancial crisis. Fragility thenbecomes instability.